Sorting out my big damp pit

[oakysmokyjoky]

I have a 2.5m x 1.5m concrete block pit that our entrance steps go round. It is filled with greensand and stones (ballast really), the 1980s membrane to the walls has failed and the moisture seeps into our integral garage and soaks through into blocks/bricks and has blown the render a few times.

For the 3rd bloody time I have dug out tons of material and managed to get down to the pathetic 38mm weep hole at over 2m depth. I've also removed all the blown render and LBC commons to leave the blocks on side retaining wall. I'm now at a decision point....as there's not a lot more I can do with the demolition hammer and want to make it reasonably OK again. I have to face the fact that I can't remove much more greensand without undermining the entire front of the right side of our house.

1. Drainage. There's a brick sized hole now that isn't quite at the bottom of the wall. Is it worth continuing down a foot so any drain point is at the lowest external point?
2. What should I form the drain to outside with? A pipe or fit a couple of engineering bricks lengthwise to leave a bigger gap
3. What and if should I line the inside of the walls with. Last time I filled the mortar gaps and blackjacked but this didn't help
4. Backfill. Is clean 20mm gravel OK or is there a better backfill material?
5. To stop any more rain getting in (I can't stop groundwater 'flow'). I thought I could hang some lintels across and terrace these with a drain - possible or a better idea is?
6. External facing. I was thinking either paint grade blocks (for a clean look) or timber/conclad cladding? Any views?

Thanks. Any advice on any or some of these points much appreciated. If anyone is in South Wiltshire near Salisbury and wants to quote please message me

 

[oakysmokyjoky]

Hi. Any ideas welcomed please!

 

[noseall]

Hi. Any ideas welcomed please!

It's one of those jobs builders run a mile from.
Overflow weep vent - boss direct into a drain.
Walls - line with waterproof geo-fabric.

 

[oakysmokyjoky]

Thanks. I'll sniff around more locally...but for this sort of thing with a few 'issues' I don't know who or what I should be asking for (expertise wise).

 

[oakysmokyjoky]

Update. I've now dug out more greensand to make a trench and managed to core drill four 72mm weep holes. Perforated drainage pipe will go inside the holes with leaf guards fixed inside. I'll try and wrap pipes with geotextile. The pipes are bedded in concrete to try and steer free water to them and out. I might blackjack the walls tonight. But anyway i'll line the temporary pit walks with geotextile and I've got 2t of 20mm gravel to slot in tomorrow, hopefully from a hiab. Then remove the wood and maybe get some prettier gravel on top . Then it's just the walls to fix and make look ok. Then I'm back to where I started!